Electronically locking selection device



Aug. 7, 1962 P. BURSTOW ETAL ELECTRONICALLY LOCKING SELECTION DEVICE Filed March 2l, 1958 4 Sheets-Shea?I 1 PIERRE BURSTOW CLAUDE MONIN BY @Mam/@k Aug. 7, 1962 P. BURSTOW ETAI. 3,048,821

ELECTRONICLLY LOCKING SELECTION DEVICE Filed March 21, 195s 4 sheets-sheet 2 FIG. 3

IVENTORS PIERRE BURSTOW CLAUDE MONIN BY @MZ @gg Aug- 7, 1962 P. BURsTvoW ETAL 3,048,821

ELECTRONICLLY LOCKING SELECTION DEVICE lNvENToRs PIERRE BURSTOW CLAUDE MONIN Aug 7, 1962 P. BURSTOW ETAL 3,048,821

ELECTRONICALLY LOCKING SELECTION DEVICE Filed March 2l, 1958 4 Sheets-Sheet 4 FIG] l N VENTORS PIERRE BURSTOW CLAUDE MONIN BY Lrm/yu United States Patent O 3,048,821 ELEC'I'RONICALLY LOCKING SELECTION DEVICE Pierre Burstow, Paris, and Claude Monin, Villenncs-sur- Seine, France, assignors to Compagnie Industrielle des Telephones, Paris, France, a French corporation Filed Mar. 21, 1958, Ser. No. 722,981 Claims priority, application France Apr. 4, 1957 13 Claims. (Cl. 340-166) This invention concerns selecting lapparatus having electronic blocking, which is applicable notably to electronic switching.

'It is known that gas diodes possess the property of becoming mutually blocked when their anode circuits are connected in parallel to a common load, as illustrated in FIGURE l. The Characteristic curve V(I) of a gas dio-de giving the voltage existing between electrodes as a function of the current supplied by the diode is diagrammatically shown in FIGURE 2. Such a characteristic curve is divided into three parts:

A part OA in which the voltage between electrodes increases very rapidly as a function of the current supplied, as long as the' tiring of the tube has not taken place; the firing occurs at the point A, the ignition voltage being VA;

A part AB, in which, the luminous discharge having been initiated, the voltage decreases while the current increases, this being the negative-resistance portion;

A ysubstantially horizontal part BC, in which the vol-tage is stabilised at Vr and regulation takes place.

If, in accordance with FIGURE l, there exists between P and Q a voltage V12-VQ higher than the ignition voltage VA, and if a tube, for example the kth, is commutated to Vp-VQ by an appropriate means represented in FIG- URE 1 by the switches T1, T2 Tk Tn, the tube tires and supplies a current I which is determined by the curve of FIGURE 2. The operating point will be at M if the loads R and r are appropriately chosen (r may be equal to Zero).

If then another tube (for example the third) is 4switched to VP-VQ, while the kth is red, it is clear that:

VA3- VCS: I/AS-d VQS since this tube practically does not conduct at the commutating operation, or:

Vas- Vos Vak- VQk: VAK'- Vck 'ir "I: Vxr

Since the voltage VXr is lower than the tiring voltage VA, the tube of order 3 cannot fire, its operating point being at U in FIGURE 2, and the uniired diodes are blocked by the diode which is in operation.

It will be seen that the presence of the load r in the cathode-circui-t has the effect of reducing the safety margin, which changes from VA-Vr, in case where r=(l, to VA-VXI. This safety margin must be appropriately chosen if a circuit arrangment such as that of FIGURE l is applied to a set of tubes in which the dispersion of the characteristics will take etect.

The diodes vmay be replaced by thyratrons, the firing of which is eiected with the aid of a third electrode, the auxiliary tiring electrode, which permits of applying a lower voltage between the two anode-cathode electrodes. In the following, the auxiliary firing electrode will be called the grid. When ired, the thyratrons are blocked in a common anode circuit in the same manner as the diodes, the firing voltage at the grid of the tube rst fired having previously been suppressed.

Such a method is utilised in the circuit arrangement illustrated in FIGURE 3 of the present application, which is derived from that which formed the subject of U.S. Patent 2,954,580, issued September 27, 1960, for Elec- 3,048,821 Patented Aug. 7, 1962 ICC tronic Selecting Device. The thyratrons are associated in series-parallel forming a matrix comprising p-lines and q-columns. The voltage VS is applied to the grids S11 Spel with the aid of switches H1 Hp. The voltage VA is applied to the anodes of the thyratrons by means of switches V1 Vq.

In order to tire a `tube such as ij in the said matrix, the following procedure is adopted:

Commutation of the voltage Vs to the grid Sij by the switch Hi,

Commutation of the voltage VA toA thel anode Az'j by the switch Vj.

Under these conditions, the tube ij res if the voltages Vs and VA are appropriately chosen,

The voltage VS is then suppressed and the voltage VA is maintained. The tube remains in the fired condition and the regulating voltage Vr remains between the anode and the cathode.

FIGURE 4 `shows the tiring characteristic curve of a thyratron giving the firing voltage Va between the `anode and the cathode as a function of the voltage Vs applied to the grid. It will be seen that the characteristic curve comprises a fork defining a zone of uncertainty in regard to the tiring voltage and an almost vertical portion, showing a critical grid voltage Vc, below which the tube cannot be red, at least without reaching excessive voltages -between the anode and the cathode. The voltage VA applied between the anode and the cathode locates the commutation point, for a grid Voltage Vs, at M so that the firing occurs. The grid voltage VS being suppressed, it is known that for a tube ij:

If I is the current flowing through the tube, there will be seen in FIGURE 3:

If r is zero, VXI: V1.

If it is then assumed that the tube ij is in operation, and the voltage VS is switched over the grid of the tube 2]', for example at S21, by the switch H2, the voltage between the electrodes of the tube 2j is VAzjVc2j=VA1j -VG=VXr, `since the tube 2j `does not conduct at the instant of the commutation. The commutation point of the tube 2J' is therefore situated at Nx in FIGURE 4. The tube 2j cannot iire.

The ldisadvantage of this method is that it has small safety margins in View of the dispersion of the characteristic curves over a Vset of tubes. The firing zone accounts for a `great deal of this lack of safety. |It is to be noted that this zone remains if, when the tube has been extinguished, the ionic germ is created by an auxiliary anode, eliminating any external photoelectric action.

The object o-f the present invention is to provide a thyratron matrix having p lines and q columns which is not attended by the aforesaid disadvantages.

The present invention has for its object :to provide a selecting apparatus comprising a matrix of gas tubes disposed in vertical and horizontal rows, the tubes situated in one Vertical row feeding a common load, while the tubes comprise -an auxiliary vtiring electrode, the apparatus being characterised in that the `blocking of a vertical row of tubes in which a tube lis tired is effected by application, to lthe firing electrode of the tubes of the said row, of a blocking voltage whose value is lower than the firing volty age.

In accordance with another feature of the invention,

a transistor is connected in the circuit of the main anode in order to effect the change-over of the control voltage of the anode.

The .auxiliary tiring electrode of a tube comprises a vertical control and a horizontal control for the purpose of either blocking `a vertical row or blocking a horizontal row.

Further features and Iadvantages of the invention will become apparent from the following description thereof with reference to FIGURES 5 to 7 of the accompanying drawings, which show byl way of example consti-notional forms of the `apparatus according to the invention.

FIGURE 5 is a diagram illustrating the basic principle of the apparatus according to the invention, comprising a matrix of thyratrons having p-lines and q-columns,

FIGURE 6 illustrates diagrammatically -a circuit arrangement for the application of the principle according to FIGURE 5, in which the switching devices comprise transistors, and

FIGURE 7 shows diagrammatically a thyratron matrix according to the invention.

'Ilhe apparatus Iillustrated in FIGURE 5 constitutes a matrix of thyratrons having p-lines `and q-colurnns The cathodes C11-to Cpq of the tubes are each connected acrom a resistance r to a common point G of a voltage source of negative polarity. The anodes A11 to Apl, A12 to Apg Am to A1,q of tubes of one column are connecte-d in parallel to a common load R, which is in turn connected to the positive terminal F of a voltage source VA through a switching device diagrammatically represented in FIG- URE 5 by a switch V1 to Vq. The lring grids ot the Itubes are connected to a common point S11 to -Spq of two resistanccs d. The free ends of one of the resistances d which iare situated in the same column are connected in parallel to a switching device diagrammat-ically represented in FIGURE 5 by a switch T1 to Tq, of which one contact is connected to `the terminal K of a voltage source Vh. The free end of the other resistance d is connected in parallel with the free end of the corresponding resistances d of a common line to a switching device diagrammeti-cally represented by a changeover switch H1 to Hp, one contact of which is connected to the terminal H of the voltage 'source VS, While the other contact thereof is connected to the terminal K of the voltage source Vh.

rIhe apparatus j=ust described operates in the following manner:

In the state which will lbe called the inoperative state in the following, that is to say when no tube is in the fire-d condition, the grids of the thyratrons such as Sii are at the potential of the point K (potential Vh). The thyratrous have a characteristic curve V(Vs) giving the tiring Voltage between the anode and the cathode as a function of the grid voltage, such as that shown in FIGURE 4.

Since the matrix is assumed to tbe in the inoperative state, if it is desired to iire a tube, for example if', the procedure is then as follows:

rlhe voltage Vs is commutated to the grids of all the tubes of the line z' by means of the reversing switch Hi. The potential of these `grids is therefore then VS.

The voltage VA, is, commutated to the anodes of the column i by meansof the switch Vj.

The. tube i1' is. then under the conditions VA and Vs (point M of FIGURE 4) and res..

When the tube. if is supplying the current I', the voltage Vh. is commutated to the gridsA of all the tubes of the column j by means of the switch Tj.

Under theseconditions, the grid Sii changes to the potential- VS+ Vh 2;

and it will in factibe seen that:

Vs- Vh=2di (mesh lI-ISJ'K) -V V V Vgn-Vb: dz=2 h Vsii ELZD' The voltages VA at the anode and Vh at the grid of the yof the column j are maintained and the grids of the line z' are changed over to the voltage Vh.

The grid Szj therefore returns to the potential Vh. Under these conditions, the tube ij regulates at the voltage Vr Iand its grid is at the voltage Vh. It will be seen that:

' if Vr is the regulating voltage of the tuJbe land I the current which it supplies.

The tube ij then being operative, if another line of grids, for example the line 2, is changed over to the voltage VS, the voltage between the cathode and the anode of the tube 2j is:

since substantially no current is flowing in the tube at the time of the change-over from VS, and the following is therefore deduced:

VAzj V023: VAxj' Von +1 l Vxr Moreover, the grid S25 is at the potential Vs+ Vn 2 Consequently, under the conditions V"r and Vs+ Vn 2 the tube 2f has its point of operation located at SX in FIGURE 4. If VS and Vh are appropriately chosen, not only will a blocking action take place at 'the anode circuit, but the potential of the grid will be lower than Vc.

The safety margins are increased b-y this double blocking. It is to `be noted that the voltage Vh may be zero without necessitating any change in the foregoing reasonlng.

It is further to be noted that it is possible without disadvantage to apply the voltage VS to the grids by column in the inoperative state (which is diagrammatically illustrated in FIGURE 5 by the dash-lined connections to the switches T1, T2 Tj, Tq). The potentials of the grids in the inoperative state are then equal to Vs-l- V11 2 -and when the voltage VS is commutated to a grid line, the grids of the commutated line change to the potential Vs, provided that they do not belong to a column in which a tube is operative, in which case the potential changes from Vh to Vsd-Vh The apparatus according to the invention permits of effecting the commutations of the grid and ring voltages without introducing any metallic contact and by using only purely electronic control means, in the present instance transistors.

In the inoperative state, the voltage Vh is continuously applied to the lines. In a preparatory phase, the Voltage VS is applied, for example, by means of a transistor and once the tube has fired, with a current flowing into the load r, it is possible to relay the ilow of this current by any appropriate means in order t-o influence the transistor which has commutated the voltage VS in order to restore the voltage Vh.

What is proposed to be elfected by means of the present invention is the blocking of the columns of grids as soon as the tube commences to conduct by applying to the grids of the fired column the voltage Vh. In the inoperative state, the voltage Vs will be applied to the column of grids, although the potential of the grids of the inoperative matrix is Vs -l'- Vn 2 The apparatus employed for this blocking of the columns is illustrated in FIGURE 6 and comprises two transistors Vj and Tj which are connected in place of the switches Vj and Tj of FIGURE 5, a set of resistances l, m and n, and a condenser C.

There is applied to the emitter of the transistor Vj the voltage VS, to its base the voltage VA and to its collector the voltage VA-Vh across a resistance m1. The collector of the transistor Vj is also connected to the anode Aij of the tube ij across the resistance R and to the base of the transistor Tj across the resistance l. 'The transistor Tjcomprises an emitter at the voltage VS, a collector at the voltage Vs across the resistance n -and connected to the grid of the tube ij across the resistance d, and the base of the transistor Tj is -fed at the Voltage VA-Vh across the resistances l and m which are connected in series and shunted by the condenser C. The letters p and q represent the multiplying points of the lines and columns of the matrix.

This apparatus operates in the following manner:

In the inoperative state, the transistor Vj, of which is at the voltage VA, is blocked, the transistor Tj, on the other hand, discharges into the grid resistance l in series with the resistance m which permits of producing between the emitter and the base exactly the required voltage for conducting. Almost exactly the voltage VS is transferred to the collector of the transistor Tj and the -grids are therefore at:

This inoperative potential Vh+ Vs 2 may be brought to the value Vs if the left-hand end of the resistance d of the potential Vj, is changed over to the potential VS by any appropriate means. At this instant, if the transistor Vj is controlled through its emitter by selectively applying thereto a potenti-al Vs it is unblocked, the Voltage VA is almost wholly transferred to the collector of Vj, and therefore to the anode circuits of the thyratrons, and the tube ij tires. This operation is due to the fact that the transistor Vj operates with its base effectively at ground potential from which follows that, when the transistor is saturated, the voltage VA reappears substantially on the collector, the resistance between collector and base being very small under those circumstances. However, it follows from this that the base of the transistor Tj will be brought -to a potential higher than VS, since the resistance l is connected to the voltage VA. The transistor Tj will be blocked and the voltage Vh will be transferred to its collector.

When the line is changed over to the voltage Vh, the grid Sii will also be at the voltage Vh.

The function of the condenser C is to introduce a time constant into the circuit of the base of the transistor Tj in order to produce a certain delay before causing the voltage to drop at the grids on the column side. The resistance m and n are protective resistances.

The apparatus according to FIGURE 7 is a thyratron matrix according to the invention, and is formed by a combination of FIGURES 5 and 6. The matrix cornprises p lines and q columns. Only the lines 1-2 i and p with which the reversing switches Hl-HZ-Hi--Hp are associated, and the columns 1 and j with which the transistors Vj/Tj and Vj/Tj respectively are associated have been sho-wn. The cathodes Cu-Cjj-Clc1 are connected in parallel to `the load resistance r1, the other end of which is connected to the point G. Similarly, the cathodes C21-C2j-C2q of the second horizontal line are connected in parallel to the resistance r2, the other end of which is connected to lthe point G. The anodes A11, A21-Am of a common vertical column are connected in parallel lto the resistance rl., the other end of which is connected to the collector of a transistor V1. Similarly, the anodes Ajj, A2j, Apj of the same vertical column are connected in parallel to the resistance rj, the other end of which is connected to the collector of the transistor Vj, etc. The grids of the tubes are each connected to the common point of two resistances d. The like free ends of the resistances d are connected together on the one hand at a common point for the horizontal line, and on the other hand at a common point for the vertical column. Thus, the grid of the tube ij is connected on the one hand through one resistance d to the centre contact of the reversing switch Hi and on the other hand through the other resistance d to the collector of the transistor Tj. The emitters of the transistors: Vj-Vj are connected respectively to appropriate devices I1-Ij, etc., which can either connect them with the point H of voltage source VS, or with a current injector, the bases of the same transistors being connected in parallel to the point F of potential VA. The collector of a transistor Vj is connected to the base of the transistor Tj through a resistance l. On the other hand, the base of the transistron Tj is connected to the potential VA-Vh through the resistances l and m. The base of the transistor Tj is also connected to the potential VA-Vh through a condenser C. The collector of a transistor Tj is permanently connected to the potential Vh through a resistance n. The purpose of the resistances l, m and n and of the condenser C has been explained with reference to FIGURE 6.

The said thyratron matrix operates in the following manner:

In the inoperative state, that is to say, when no tube has red, the transistors Vj-Vj-Vq are blocked, the devices I1, Ijq connecting the emitters thereof to a potential Vs lower than the potential VA to which the bases are connected. On the other hand, in the same inoperative state, the transistors T1, Tj, Tc1 each conduct in a circuit including the corresponding bias resistance l in series with a resistance m, which is yin turn connected t-o a voltage source VA-Vh, whereby it is possible to obtain the exact voltage necessary for conducting. Almost all the voltage Vs at the emitter is transferred to the collector, so that the grid of -all the tubes are in the inoperative state at the potential Vh-l- Vs 2 In order to effect the tiring of the tube ij, the switch Hi is rst changed over, the effect of which is to apply a potential VS to one end of the grid resistance d, the other resistance already being at the potential VS through the collector of the transistor Tj. The potential of the grid Sij therefore changes from the value to the value Vs. If a current is now injected into or a voltage is now applied to the emitter of the transistor Vj by means of the device lj, the said transistor is unblocked and the voltage VA is almost entirely transferred to the collector of Vj, and therefore to the anode circuits of all the thyratrons of the column j through the resistance Rj. The tube ij will therefore be fired. Moreover, the base of the transistor Tj is thus brought to a potential higher than VS, since the resistance l connects the collector of Vj to the base of Tj, and consequently the transistor Tj will be blocked and its collector will be brought to the voltage Vh through the resistance n. On the other hand, as soon as the tube ij has been red and has supplied 4a current through its cathode across the resistance ri, the said current produces through an appropriate device a further change-over of the reversing device Hi, which has the effect of restoring it to its initial position. Therefore, at this instant, the ends of the resistances d of the tube ij are both at the potential Vh. The grid Sj is also at.

7 the potential Vh and the tube if operates at its regulating voltage.

The blocking of the tired tube is thus effected by the potential Vh applied to its grid. It is then no longer possible, as long as the tube ij is conducting, to tire another tube of the `same column j, but it is possible to re another tube of the same line i, the potential of the grid Sij in this case changing from the value Vh to the value whereby complete reliability of its operation is ensured. To sum up, in order that any tube may ire, the rst condition is that the voltage Vs should be applied to the horizontal'l-ine of the grids and to the vertical column of the grids. The second condition is that the voltage VA should be applied to the vertical column of the anodes.

The reversing switch Hi which changes over the voltage from Vh to VS and vice versa may be of any appropriete form. It is sufficient to indicate that the voltage Vh continuously applied to the lines changes to the voltage Vs during the phase of the preparation for the tiring of a tube of the corresponding line, for example by means of a transistor. Once the tube has fired, and a current is owing across the resistance r, the ilow of this current can be relayed by any appropriate means in order to influence the transistor for restoring the voltage Vh.

We claim:

1` A selecting apparatus having electronic blocking, comprising a matrix of gas tubes disposed in horizontal rows and vertical rows, each tube having a plurality of electrodes including an anode and an auxiliary tiring electrode, the tubes situated in each common vertical row having their anodes connected to a common load, means including switching means for blocking a vertical row of tubes by the superposed elects of the drop of potential in the common load and by application to the auxiliary tiring electrode of a blocking voltage whose value is lower than the tiring voltage, a pair of resistances for each tube with the auxiliary tiring electrode of the tube connected to a common point of said resistances, control means for each tube including a vertical control and a horizontal control, means for connecting one of said resistances to a respective vertical control and means for connecting the other resistance to a respective horizontal control, means for `selectively connecting each one of said controls independently one from the other either to a tiring voltage or to a blocking voltage, means for applying the anode Voltage including a further vertical control, the ring voltage being applied, at rest, to the auxiliary electrode by way of the vertical control, the same ring voltage being applied, in operation, by way of the horizontal control so that a tube is tired by setting into position of operation the horizontal and vertical controls, the output itself of said tube automatically setting the horizontal control in its initial position of rest, and the placing into operation lof the vertical control automatically cau-sing the switching of the vertical control into theA blocking position thereof, the effect of these automatic s witchingsy after tiring of the tube resulting in the blocking in the rest position of the tubes of the same vertical rowy as the tired tube and the blocking of the red tube in its operative state.

2; A selecting apparatus according to claim 1, wherein said horizontal and vertical controls each include a commutation device, and furthery comprising means for applying a bias to the end of one `of the resistances by means ofthe commutation device for the horizontal control and means for applying a bias to the other end of the other resistanceV by means of the commutation device for the vertical control.

3, A selecting; apparatus according to claim l wherein for said one tube theV commutation of the voltage of the auxiliary tiring elect-rode and of the voltage of the anode is eiected with the aid of a transistor, so as to block the firing electrodes of the other tubes in a respective row as soon as said one tube commences to conduct, a rst transistor being connected in the circuit of the tiring electrode to eiect the change-ove-r of the bias at the tiring electrode from the blocking value to the tiring value and then to the blocking value and a second transistor being connected in the circuit of the anode to eect the change-over of the control voltage of the anode.

4. A selecting apparatus according to claim 1 wherein there is associated with each vertical row a set of two transistors, the irst 'of which simultaneously controls the change-over of the anode voltage for eacn tube of said vertical row and the blocking or unblocking of the second transistor, the latter successively applying to the auxiliary firing electrode of each tube of said vertical row the tiring voltage when the second transistor conducts and the blocking voltage when it is blocked.

5. A selecting apparatus according to claim 4, wherein the collector of the second transistor is connected to the auxiliary tiring electrode for its vertical control, the base of this transistor being connected across a resistance to the collector of the irst transistor, said collector of the first transitor also being connected to the anode of each of the tubes of the respective vertical row, biases being applied to the bases and to the collectors of the transistors and control currents being applied to the emitters, so that when the rst transistor is blocked the second conducts and when thte rst transistor conducts the second is blocked.

6. A selecting apparatus according to claim 4, wherein the base of the second transistor is connected to a particular voltage through a resistance, a condenser being provided to shunt the resistance in such manner that the blocking commutation of the tiring electrode is slightly staggered in relation to the application of voltage to the anode.

7. In a selecting apparatus having a matrix of gaseous discharge tubes disposed in horizontal and vertical rows each tube being provided with a plurality of electrodes including two main electrodes and an auxiliary ring electrode, the tubes situated in each common vertical row having one of .their respective -main electrodes connected to a common load circuit, and the tubes situated in a common horizontal row having their respective grids each connected to two respective resistance elements, the free ends of one of each of the two resistance elements of each tube in a respective common horizontal row being connected together into a rst common energizing circuit and the free ends of the other one of each of the two resistance elements of each tube in a respective common vertical row being connected together in a second energizing circuit, the improvement essentially consisting of switching means to enable selective tiring of only one gaseous discharge tube in each vertical row while enabling selective firing of a gaseous discharge tube disposed in the same horizontal row as said last-mentioned `one tube, comprising a rst switching means for each vertical row operatively connected to a respective common load circuit for normally applying a voltage to said one main electrodes of each tube disposed in said ventical row which is insufficient to enable ring of any ofthe tubes in said vertical'row, a second` switching means for each horizontal row to selectively apply toeach of said other free ends of the respective resistance elements of said horizontal row ltwo voltages of different value, a third switching means for each vertical row operatively connected with the free ends of said one resistance elements of the rtubes disposed in said respective vertical row for selectively applying one of two voltages tov said one resistance elements, said irst, second and third switching means each having two operating states, selecting means for selectively tiring one of said tubes including rst means operatively connected with said rst switching means for selectively switching a preselected one of said first switching means from one state to the other state and second means operatively connected with said second switching means for selectively switching a preselected one of said second switching means from one state to the other state, connecting means operatively connecting a first switching means with a third switching means belonging to a respective vertical row to selectively switch the respective third switching means from its pre-existing state to the other upon switching of the corresponding first switching means by a respective first means,

8. In a selecting apparatus having a matrix of gaseous discharge tubes disposed in horizontal and vertical rows, each tube being provided with a plurality of electrodes including two main electrodes and an auxiliary firing electrode, the tubes situated in each common vertical row having one of their respective main electrodes connected to a common load circuit, and the tubes situated in a common horizontal row having their respective grids each connected to two respective resistance elements, the free ends of one of each of the two resistance elements of each tube in a respective common horizontal row being connected together into a first common energizing circuit and the free ends lof the other one of each of the -two resistance elements of each tube in a respective common vertical row being connected together in a second energizing circuit, the improvement essentially consisting of electronic switching means to enable selective firing of' only one gaseous discharge tube in each vertical row while enabling select-ive firing of a gaseous discharge tube disposed in the same horizontal row as said last-mentioned one tube, comprising a first transistorized switching means for each vertical row operatively connected to a respective co-rnrnon load circuit for normally applying a voltage to said one main electrodes of each tube disposed in said vertical row which is insufficient to enable firing of any of the tbes in said vertical rowJ a second switching means for each horizontal row to selectively apply to each of said other free ends of the respective resistance elements of said horizontal ro-w two voltages of different value a third transistorized switching means for each vertical row operatively connected with the free ends of said one resistance elements of the tubes disposed in said respective vertical row for selectively applying one of two voltages to said one resistance elements, said first, second and third switching means each having two operating states, selecting means for selectively firing one of said tubes including first means operatively rconnected with said first transistorized switching means for selectively switching a preselected one of said first switching means from one state to the other state and second means operatively connected with said second switching means for selectively switching a preselected one of said second switching means from one state to the other state, connecting means operatively connecting a first switching means with a third switching means belonging to a respective vertical row to selectively switch the respective third switching means from its preexisting state to the other upon switching of the corre' sponding first switching means by a respective first means, and current responsive means operatively associated with a respective tube for returning the respective second switch means belonging to the horizontal row in which the fired tube is disposed to its pre-existing state and thereby blocking said fired tube.

9. A selecting apparatus comprising a matrix of gaseous discharge tubes disposed in horizontal and vertical rows, each tube being provided with a plurality of electrodes including two main electrodes connected in a discharge circuit and an auxiliary firing electrode, the tubes situated in each common vertical row having one o-f their respective main electrodes connected to a common load circuit, and the tubes situated in a common horizontal row having their respective grids connected each to two resistance elements, first circuit means operatively connected to all the free ends of one of the two resistance elements associated with the grids of the tubes in a respective horizontal row, second circuit means operatively connected to all the free ends of the other of the two resistance elements associated with the grids of the tubes in a respective vertical row, first switch means in each first circuit means for selectively applying thereto, on the one hand, a first voltage which prevents firing of any tubes in the corresponding horizontal row and, on the other, a second voltage which enables firing of a preselected one of the tubes thereof, second switch means in each common load circuit for selectively applying to the one main electrode of the tubes in a corresponding vertical row a firing voltage enabling firing of the tube to the grid resistance element of which is also applied said second voltage by a respective first switch means, third switch means in each second circuit means for selectively applying thereto on the one hand, a first voltage which enables firing of a tube associated with its circuit upon application to its grid circuit of said second voltage by said firs-t switch means and, on the other, a second voltage which effectively provides a blocking voltage at the grid of a tube associated with its circuit, to the grid circuit of which is also applied said first voltage by a corresponding first switch means, means operatively connected with the discharge circuit of a respective tube for changing the iirst switch means associated therewith to apply to a corresponding iirst circuit means said first voltage upon firing of said tube, first control means for selectively energizing a preselected second switch means, second control means for selectively changing a preselected first switch means to apply to a corresponding first circuit means said second voltage, and connecting means operatively connecting the second switch means with the third switch means of a respective vertical row to change the asociated third switching means to apply to said second circuit means said second voltage upon energization of the corresponding second switch means by said first control means to thereby effectively provide a blocking voltage at the grid of each tube in the vertical row associated with said third switch means.

l0. A selecting apparatus comprising a matrix of gaseous discharge tubes disposed in horizontal and vertical rows, each tube being provided with a plurality of electrodes including two main electrodes connected in a discharge circuit and an auxiliary firing electrode, the tubes situated in each common vertical row having one of their respective main electrodes connected to a common load circuit, and the tubes situated in a common horizontal row having their respective grids connected each to two resistance elements, first circuit means operatively connected to all the free ends of one of the two resistance elements associated with the grids of the tubes in a respective horizontal row, second circuit means operatively connected to all the free ends of the other of the two resi-stance elements associated with the grids of the tubes in a respective vertical row, first switch means in each first circuit means for selectively applying thereto, on the one hand, a first voltage which prevents firing of any tubes in the corresponding horizontal row and, on the other, a second voltage which enables 'firing of a preselected one of the tubes thereof, second switch means including a transistor in each common load circuit for selectively applying to the one main electrode of the tubes in a corresponding vertical row a firing voltage enabling firing of the tube to the grid resistance element of which is also applied said second voltage by a respective first switch means, third switch means including a transistoi in each second circuit means for selectively applying thereto on the one hand, a first voltage which enables firing of a tube associated with its circuit upon application to its grid circuit of said second voltage by said first switch means and upon application to the one main electrode thereof of said firing voltage by said second switch means and, on the other, a second voltage which effectively provides a blocking voltage at the grid of a tube associated with its circuit, to the grid circuit of which is also applied said first voltage by a corresponding first switch means, means aoeasal operatively connected with the discharge circuit of a re spective tube for changing the rst switch means associated therewith to apply to a corresponding first circuit means said first voltage upon tiring of said tube, irst control means for selectively energizing a preselected second switch means, second control means for selectively changing a preselected first switch means to apply to a corresponding rst circuit means said second voltage, and connecting means operatively connecting the second switch means with the third switch means of a respective vertical row to change the associated third switching means to apply to said second circuit means said second voltage upon energization of the corresponding second switch means by said first control means to thereby effectively provide a blocking voltage at the grid of each tube in the vertical row associated with said third switch means, each transistor including a base, a collector and an emitter, and said connecting means operatively connecting the collector of the transistor in said second switch means with the base of the transistor in said third switch means.

1l. A selecting apparatus comprising a matrix of gaseous discharge tubes disposed in horizontal and vertical rows, each tube being provided with a plurality of electrodes including two main electrodes connected in a discharge circuit and an auxiliary iiring electrode, the tubes situated in each common vertical row having one of their respective main electrodes connected to a common load circuit, and the tubes situated in a common horizontal row having their respective grids connected each to two resistance elements, first circuit means operatively connected to all the free ends of one of the two resistance elements associated with the grids of the tubes in a respective horizontal row, second circuit means operatively connected to all the free ends of the other of the two resistance elements associated with the grids of the tubes in a respective vertical row, first switch means in each first circuit means lfor selectively applying thereto, on the one hand, a first voltage which prevents firing of any tubes in the corresponding horizontal row and, on the other, a second voltage which enables tiring of a preselected one of the tubes thereof, second switch means including a transistor in each common load circuit for selectively applying to the one main electrode of the tubes in a corresponding vertical row a firing voltage enabling firing of the tube to the grid resistance element of which is also applied said second voltage by a respective first switch means, third switch means including a transistor in each second circuit means for selectively applying thereto on the one hand, a first voltage which enables firing of a tube associated with its circuit upon application to its grid circuit of said second voltage by said first switch means and upon application to the one main electrode thereof of said firing voltage by said second switch means and, on the other, a second voltage which effectively provides a blocking voltage at the grid of a tube associated with its circuit, to the grid circuit of which is also applied said lfirst voltage by a corresponding iirst switchrmeans, means operatively connected with the discharge circuit of a respective tube for changing the iirst switch means associated therewith toy apply to a corresponding first circuit means said first voltage upon firing of said tube, first control means for selectively energizing a preselected second switch means, second control means for selectively changing a preselected first switch means to apply to a correspending first circuit means said second voltage, and connecting means operatively connecting the second switch means with the third switch means of a respective vertical row to change the associated third switching means to apply to said second circuit means said second voltage upon energization of the corresponding second switch means by said iirst control means to thereby effectively provide a blocking voltage at the grid of each tube in the vertical row associated with said third switch means, each transistor including al base, a collector and an emitter, each transistor of said second switch means being normally non-conducting and each transistor of said third switch means being normally conducting, and said connecting means operatively connecting the collector of the transistor in said second switch means with the base of the transistor in said third switch means in such a manner that upon actuation of a respective control means the transistor of the second switch means is rendered conductive and the transistor of the third means is rendered non-conductive.

l2. In a selecting apparatus having a matrix of gaseous discharge tubes disposed in horizontal and vertical rows, each tube being provided with a plurality of electrodes including two main electrodes and an auxiliary firing electrode, the tubes situated in each common vertical row having one of their respective main electrodes connected to a common load circuit, and the tubes situated in a common horizontal row having their respective grids each connected to two respective resistance elements, the free ends of one of each of the two resistance elements of each tube in a respective common horizontal row being connected together into a first common energizing circuit and the free ends o-f the other one of each of the two resistance elements of each tube in a respective common vertical row being connected together in a second energizing circuit, the improvement essentially consisting of switching means to enable selective tiring of only one gaseous discharge tube in each vertical row while enabling selective firing of a gaseous discharge tube disposed in the same horizontal row as said last-mentioned one tube, comprising a first switching means Afor each vertical row operatively connected to a respective common load circuit for normally applying a voltage to said one main electrodes of each tube disposed in said vertical row which is insufficient to enable firing of any of the tubes in said vertical row, a second switching means for each horizontal row to selectively apply to each of said other free ends of the respective resistance elements of said horizontal row two voltages of diiierent value, a third switching means for each vertical row operatively connected with the free ends of said one resistance elements of the tubes disposed in said respective vertical row for selectively applying one of two voltages to said one resistance elements, said first, second and third switching means each having two operating states, selecting means for selectively ring one of said tubes including first means operatively connected with said rst switching means for selectively switching a preselected one of said first switching means from one state to the other state and second means operatively connected with said second switching means for selectively switching a preselected one of said second switching means from one state to the other state, connecting means operatively connecting a iirst switching means with a third switching means belonging to a respective vertical row to selectively switch means the respective third switching means from its' preexisting state to the other upon switching of the corresponding first switching means by a respective first means, and current responsive means operatively associated with a respective tube for returning the respective second switch means belonging to the horizontal row in which the fired tube is disposed to its preexisting state and thereby blocking said fired tube.

13. In a selecting apparatus having a matrix of gaseous discharge tubes disposed in horizontal and vertical rows, each tube being provided with a plurality of electrodes including two main electrodes and an auxiliary firing electrode, the tubes situated in each common vertical row having one of their respective main electrodes connected to a common load circuit, and the tubes situated in a common horizontal row having their respective grids each connected to two respective resistance elements, the free endsof one of each of the two resistance elements of each tube in a respective common horizontal row being connected together into a first common energizing circuit and thefree ends of the other one of 13 each of the two resistance elements of each tube in a respective common vertical row being connected together in a second energizing circuit, the improvement essentially consisting of electronic switching means to enable selective ring of only one gaseous discharge tube in each vertical row while enabling selective ring of a gaseous discharge tube disposed in the same horizontal row as said last-mentioned one tube, comprising a first transistorized switching means for each vertical row operatively connected to a respective common load circuit for normally applying a voltage to said one main electrode of each tube disposed in said vertical row which is insucient to enable firing of any of the tubes in said vertical row, a second switching means for each horizontal row to selectively apply to each of said other free `ends of the respective resistance elements of said horizontal row two voltages of dilerent value, a third transistorized switching means for each Vertical row operatively connected with the free ends of said one resistance elements of the tubes disposed in said respective vertical row for selectively applying one of two voltages to said one resistance elements, said rst, second and third switching means each having two operating states, selecting means for selectively ring one of said tubes including rst means operatively connected with said rst transistorized switching means for selectively switching a preselected one of said rst switching means from one state to the other state and second means operatively connected with said second switching means for selectively switching a preselected one of said second switching means for one state to the other state, connecting means operatively connecting a first switching means with a third switching means belonging to a respective vertical row to selectively switch the respective third switching means from its pre-existing state to the other upon switching of the corresponding rst switching means by a respective -rst means.

References Cited in the le of this patent UNlTED STATES PATENTS 2,049,763 De Forest Aug. 4, 1936 2,056,301 Schroter Oct. 6, 1936 2,136,441 Karolus Nov. 15, 1936 2,428,811 Rajchrnan Oct. 14, 1947 2,434,989 Christian Jan. 27, 1948 2,655,605 Hartley Oct. 13, 1953 2,691,151 Toulon Oct. 5, 1954 2,693,593 Crosman Nov. 2, 1954 2,769,865 Faulkner Nov. `6, 1956 2,774,813 Livingston Dec. 18, 1956 2,825,889 Henle Mar. 4, 1958 2,886,797 Gardberg May 12, 1959 2,889,537 Elliott .lune 2, 1959 2,900,572 Lucas et al. Aug. 18, 1959 OTHER REFERENCES Control Engineering, December 6, pp. 70-76, by R. Brown et al. 

